Core box seal strip



Jan. 22, 1963 E. F. PETERSON 3,074,129

CORE BOX SEAL STRIP Filed June 13, 1960 Unite States Patent @fifice3,074,129 Patented Jan. 22, 1963 3,874,129 CGRE BOX SEAL STRIP Edwin F.Peterson, R0. Box 151, Neponset, Ill. Filed June 13, 1960, Ser. No.35,483 Claims. (Cl. 22-43) This invention relates to core box sealingmeans in the form of a resilient strip providing an effective barriercounteracting fluid passage between surface areas of coacting matingcore box parts.

The general environment and basic application of a sealing strip of thecharacter herein described and disclosed is well expressed in acopending application, Serial No. 17,999, filed March 28, 1960, directedto a Core Box Sealing Strip and Method of Attachment, of which theinstant application comprises a continuation-in-part.

An object of the present invention is to provide a seal strip forattachment with a core box part by cemented retention in a groove thatis initially cut into a matching surface of such a part to carry thestrip in an effective sealing position subject to direct physicalengagement with a matching surface area of a complementary core boxpart.

Another object is to provide duplicate matching and coacting seal stripsthat are oriented along mating core box surface areas for compressivesealing contact, seal to seal, to prevent blowby or leakage of core boxfluid and/ or core forming materials from within the cavity of the corebox assembly.

A still further object is to provide a resilient seal strip having apredetermined cross sectional contour to accommodate change in shape ofthe strip under operative sealing conditions while fixedly secured in anorientation and accommodation groove in a core box part. Such stripshape or contour includes certain rounded clearance corners at thelateral terminal edges of the strip whereby to prevent possibleinterference by the strip material between box parts which might tend tohold the matching surfaces apart or out of contact, thus eliminating anobjectionable condition in the core blowing art while using a strip ofthe nature herein disclosed.

Other objects and advantages of the seal strip of the present inventionshall hereinafter appear in or become apparent from the followingdetailed description having reference to the accompanying drawingforming a part of this specification.

In the drawings:

FIG. 1 is an end view of a sealing strip of the present invention whichis preferably fashioned as an extrusion of resilient material of anysuitable length or lengths that may be applied end to end or cut toselected lengths;

FIG. 2 is a fragmentary perspective view of a core box partincorporating a sealing strip in the manner in which it is normallycarried and employed as a scaling instrumentality between matingsurfaces of core box parts;

FIG. 3 is a vertical sectional view of a pair of coacting matching corebox parts with a sealing strip shown in elevation in operative relationbetween such parts, this view including a diagrammatic illustration ofone kind of orientation means in the form of a pin and hole arrangement;

FIG. 4 is a fragmentary detail sectional view of adjacent sealing stripand box slot elements to show a modified variation of means tocounteract possible box part separation under certain conditions ofassembly of said sealing arrangement; and

FIG. 5 illustrates, in vertical cross section, a fragmentary core boxsection employing a modified combination of sealing strip means.

Referring to FIG. 1, the seal strip 1 is substantially the same as thestrip defined and described in the copending application Serial No.17,999 with certain contour variations to be hereinafter explained Ingeneral, strip 1 comprises a tubular member having a crown 2 as thesealing head disposed to the upper side of the diametral line AB, withthe major portion of the strip having a half-round retention body 3lying to the lower or opposite side of line A-B. An opening 4 of generalhalfmoon shape in cross section is provided longitudinally of the strip,this opening being located eccentrically or offset downwardly from thecenter point C, from which point a radius R generates and defines thehalf circle exterior surface of the retention body portion of strip 1.

The opening 4, by its placement in the cross sectional face of thestrip, establishes a heavy wall 5 forming a bridge including the crown 2and extending between the lateral limits 6 and 7 of the strip at itsmaximum width. The rest of the wall portion of the strip provides thecurved half round wall 8 providing the retention contour portion of thisseal strip 1 in the form of a thin midsection 9 and heavier side wallsections 10 and 11 joining the bridge wall 5. In addition, the lateraledges of the strip 1 at the limits 6 and 7, include curved or roundedcorners 12 and 13 for purposes to be described.

While the sealing strip in the copending application Serial No. 17,999was attached to one matching surface of mating core box parts throughthe crown 2 for sealing entry into a half round recess or groove, thepresent concept secures the greater body portion of the strip 1 into anaccommodation groove formed into one of the core box parts. As shown inFIG. 2, box part 14 is provided in any suitable way with a slot orgroove 15 of half-circular cross sectional shape so that the diametralportion of the groove is coincident with the coplanar surface portions16 and 17 of the parting surface of part 14.

To assemble the strip 1 in the box part 14, after groove 15 is supplied,a suitable cement or adhesive 18 is applied to the slot or groove wallarea, and a length of strip is layed or depressed into the groove forretention to occupy the position illustrated in FIG. 2. This assembly ofthe strip with box part 14 will dispose the crown 2 upwardly of thesurfaces 16 and 17 to establish a raised seal means above the surface ofthe box part 14. The crown 2 is supported by the upwardly curved bridge5.

By assembling a matching core box part 18 with its part 14 as in FIG.3,oriented by pin and hole means such as pin 19 and hole or bore 2%, thecrown of strip 1 is contacted by the flat undersurface 21 of part 18 anddepressed or deformed inwardly into a shape such as diagrammaticallyshown in FIG. 3. Under closed box condition, the bridge 5 isstraightened out to establish a pressure contact of the crown of sealstrip 1 on surface 21, simultaneously inducing internal lateral stripdistortion tending to spread or pressure activate the wall sections 10and 11 into greater sealing action toward the sides of groove 15 in thedirection of the arrows shown in FIG. 3. Dot and dash lines in FIG. 3show initial core box part contact with the strip prior to face to facesurface contact of the matching surface areas 16-47 and 21.

The box parts are clamped face to face when in seated and sealedpositions prior to core blowing. Since the crown of the seal strip willat all times tend to return to its undeformed shape, removal of the corebox clamps to permit part separation will allow the seal member to aidin box part separation by its inherent faculty of returning to itsexpanded or extended undeformed shape as illustrated in FIGS. 1 and 2.In this respect the strip not only seals the contacted parting surfacesof the core box parts, but the strip also provides a means for urgingbox parts apart at the parting surfaces after core blowing and box clampremoval, or at any time that separation is desired.

The strip 1 is made half round with a diameter D and having the radiusR. Slot or groove 15 is milled half round to match and receive the stripin cemented relation as explained. Obviously, a certain amount oftolerance is possible regarding the true depth of groove 15. The idealand easily obtained cut of groove is normally readily and accuratelypossible with a little care. The crown, however, is well adapted tofunction in its designed capacity even if the groove should be cut a fewthousandths deeper than needed.

Should a somewhat shallower groove result with a lighter cut by a fewthousandths, the strip body will be raised accordingly to cause a slightelevation of the strip. Under the latter conditions, pressure upon crown2, acting in the usual manner, will tend to expand the bridge 5laterally. With a strip having sharp corners at 12 and 13, as does thestrip in the copending application Serial No. 17,999, it has been foundthat such corners tend to creep or feather laterally between opposingfaces of the core box parts resulting in some face to face separationeven under clamped conditions. This will affect the dimentional accuracyof the cores developed.

This same condition may result under conditions wherein the strip hasbeen slightly tilted in cementing it into the groove. This may occurover a short length or over a greater length, although this conditionneed not normally happen under careful attachment.

To remedy such situations that tend to prevent good faceto face contactof the core box parts, the extreme lateral corners of the strip arebroken or rounded a predetermined amount as at 12 and 13. This removesthe strip material that would normally tend to feather or expandlaterally away from the vertical strip groove walls to move over or uponthe adjacent surfaces 16 or 17 of core box part 14. Under uncompressedconditions, slight clearances will flank the strip sides, but with corepart pressure applied to crown 2, the bridge 5 expands laterally andtends to fill such clearance areas somewhat as indicated in FIG. 3. V

The simple, ideal and cheapest way to take care of the discussedeventuality is to extrude strip 1 as described and having the roundedcorners along its lateral edges. Another way to prevent core box partseparation by strip material interference is shown in FIG. 4. Here strip22 has sharp corners such as 23, and box part 24 carries the groove 25to accommodate the strip. The groove 25 is rounded at 26, along bothedges only one 'of which is shown, so as to create a clearance areaadjacent the top parting line surface 27 of part 24. Any forced lateralexpansion of the material of strip 22 will be accommodated in theclearance area of the box part. The latter arrangement, however, entailsadded work on the slot or groove corners involving a further operationadding to the overall cost of the seal assembly.

By securing the seal strip in housed and nested relation below the corebox surface, the strip does not tend to provide a projection in the formof a surface obstruction. Danger of strip damage by contact with anothercore box part, or from some other shop tool or the like, is reduced to aminimum. While the crown is raised as described, the surface contourthereof blends into the core box surface to readily ward off any directpart con- :tact. In addition, the resiliency of the strip plus itshollow center will permit crown depression upon any severe part or toolcontact, thus further warding off damage to the strip and deflecting thecontacting in strumentality away from the strip location.

With the recessed strip of this character it is a simple matter toemploy a dryer in connection with core transfer from the core box to thedryer for oven drying, a

practice well known to those skilled in the art. .The

As a further advantage in connection with the use of a dryer, the crownof the present strip provides a given raised projection in uncompressedcondition. Dryers are normally made deeper in their cavity areas toprevent crushing or any tendency to change the shape of the core per seupon application. Turning the core box part to transfer the core intothe dryer will let the core move into place from core box part to dryerover the slight excess clearance provided without damage.

Dryers employed with core boxes having the seal strip herein describedcan be made to the exact dimensions of the core since placing the dryerupon the box part having the core will hold the dryer slightly raisedupon the seal strip crown. In this way the necessary clearances areautomatically supplied by the strip and upon turning the part and dryerover, the core will readily settle or move into the dryer for transferto a drying oven.

The foregoing explanation of the seal strip of this invention indicatesthe efiiciency and versatility of the seal assembly. One othercontemplated application of' the strip is illustrated in FIG. 5 toprovide a dual seal means by attaching identical seal strips in opposingrelation on coacting mating core box surfaces. Box parts 28 and 29oriented by pin means 30 carry strips 3 1 and 32 respectively in boxgrooves 33 and 34. Since'the opposing crowns 35 and 36 each add tonormal boxpart separation under uncompressed condition, the normal gap37 between the parts is doubled in size. Also, the resilient reactivepressure of the two seals, under box closure conditions, will contributegreater power tending toward box part separation after core blowing andbox clamp removal.

The seal means in FIG. 5 is, therefore, a seal having great latitude ofaccommodation .to correct many variations or inaccuracies in the corebox members, while at all times providing an effective and etlicientfluid seal for such members.

The foregoing description relates to some preferred seal structuresillustrative of the concept of the present invention. Certain changes inthe individual elements or in their combinations are contemplatedwithout departing from the fundamental inventive concept hereindisclosed. The extent of such modifications shall, however, be governedby the breadth and scope of the language appearing in the followingclaimed subject matter relating to the core box seal strip of thisinvention.

What I claim is:

l. A sealing structure for a pair of mating core box sectionscomprising, in combination, a first core box section having a partingline surface thereon, a second core box section having a matchingparting line surface thereon for abutting surface to surface contactwith the corresponding surface of said first section, one of saidsections having a groove formed into its parting line surface to providea cavity located entirely to one side of said parting line divisionbetween said sections with the parting line surface of the other sectionproviding the closure means for the groove along the common partingplane of said core box sections, and a resilient deformable seal striptightly secured into said groove comprising a hollow base portionnormally filling said groove under undeformed conditions provided withan exterior surface shaped to follow the contour of said groove, saidstrip having a convex crown portion normally extending beyond saidgroove over the entire width of said groove under undeformed conditions,for direct surface contact with the outer parting line surface of thematching section to induce groove body deformation by the exposed bowedface thereof and across the groove width by said matching section, saidgroove having a cross sectional area at least as great as that of saidseal strip and the edge of the convex crown portion of said sealextending in the same plane as the parting line surface of the core boxsections with said edge of said strip being substantially colinear withthe edge of said groove.

2. In the combination set forth and defined in claim 1, wherein abonding material secures the seal strip in fixed relation upon groovewalls to confine the compressive action on said strip to the crownportion thereof and toward a central portion of said strip that liesremote from the wall portions of the groove.

3. In the structure defined in claim 1, wherein edge portions of theseal strip and adjacent edge portions of the groove walls are disposedsubstantially in a common plane lying coincident with the parting inesurfaces of the core box sections, and wherein at least one set of saidedge portions are rounded off to establish clearance areas flanking theedge portions of the strip whereby to accommodate any possible laterallyoutward feathering of said strip while under deformation.

4. In the apparatus of claim 1, wherein the hollow seal strip provides aheavier bridge portion adjacent the parting line and a thinner wallportion adjacent the bottom of said groove.

5. in the combination set forth and defined in claim 1 wherein said corebox sections containing similar aligned grooves receive similar abuttingseal strips.

References Cited in the file of this patent UNITED STATES PATENTS2,510,417 Rehklau June 6, 1950 2,661,229 Slaughter Dec. 1, 19532,815,549 Olson Dec. 10, 1957 2,963,766 Wallace Dec. 13, 1960

1. A SEALING STRUCTURE FOR A PAIR OF MATING CORE BOX SECTIONSCOMPRISING, IN COMBINATION, A FIRST CORE BOX SECTION HAVING A PARTINGLINE SURFACE THEREON, A SECOND CORE BOX SECTION HAVING A MATCHINGPARTING LINE SURFACE THEREON FOR ABUTTING SURFACE TO SURFACE CONTACTWITH THE CORRESPONDING SURFACE OF SAID FIRST SECTION, ONE OF SAIDSECTIONS HAVING A GROOVE FORMED INTO ITS PARTING LINE SURFACE TO PROVIDEA CAVITY LOCATED ENTIRELY TO ONE SIDE OF SAID PARTING LINE DIVISIONBETWEEN SAID SECTIONS WITH THE PARTING LINE SURFACE OF THE OTHER SECTIONPROVIDING THE CLOSURE MEANS FOR THE GROOVE ALONG THE COMMON PARTINGPLANE OF SAID CORE BOX SECTIONS, AND A RESILIENT DEFORMABLE SEAL STRIPTIGHTLY SECURED INTO SAID GROOVE COMPRISING A HOLLOW BASE PORTIONNORMALLY FILLING SAID GROOVE UNDER UNDEFORMED CONDITIONS PROVIDED WITHAN EXTERIOR SURFACE SHAPED TO FOLLOW THE CONTOUR OF SAID GROOVE, SAIDSTRIP HAVING A CONVEX CROWN PORTION NORMALLY EXTENDING BEYOND SAIDGROOVE OVER THE ENTIRE WIDTH OF SAID GROOVE UNDER UNDERFORMEDCONDITIONS, FOR DIRECT SURFACE CONTACT WITH THE OUTER PARTING LINESURFACE OF THE MATCHING SECTION TO INDUCE GROOVE BODY DEFORMATION BY THEEXPOSED BOWED FACE THEREOF AND ACROSS THE GROOVE WIDTH BY SAID MATCHINGSECTION, SAID GROOVE HAVING A CROSS SECTIONAL AREA AT LEAST AS GREAT ASTHAT OF SAID SEAL STRIP AND THE EDGE OF THE CONVEX CROWN PORTION OF SAIDSEAL EXTENDING IN THE SAME PLANE AS THE PARTING LINE SURFACE OF THE COREBOX SECTIONS WITH SAID EDGE OF SAID STRIP BEING SUBSTANTIALLY COLINEARWITH THE EDGE OF SAID GROOVE.